1. A study of cardiovascular risk factors compared heavy smokers, light smokers, and nonsmokers. Both men and women were included in the study so that the two factors are smoking level and gender. There were 25 subjects included in each of the combinations of gender and smoking level. One of the variables measured was the heart rate after six minutes of exercise. A two-way ANOVA is to be performed on this data. The degrees of freedom for error are
A. 19.
B. 144.
C. 6.
2. An experiment was conducted to determine the effects of three different pesticides (P1,P2,P3) on the yield of three different varieties of citrus tree (V1,V2,V3). Six trees of each variety were randomly selected from the orchard, and the three pesticides were than randomly assigned to the trees; two trees for each pesticide. Yields of fruit, in bushels per tree, were obtained after the test period.
The two factors being studied in this experiment are
A. yield and pesticide.
B. yield and variety.
C. pesticide and variety.
3. In many sports, there is a debate over the use of high-tech equipment to improve performance. A recent study in golf centered on both the use of high-tech equipment and whose performance would actually be improved. In the study, 60 golfers were selected at the beginning of the season: twenty at the beginner's level, twenty at the intermediate level, and twenty who were considered advanced golfers. Each level of golfer was randomly divided into two groups of 10 each. One group was given a titanium driver, and the other group was given weekly golf lessons from a pro. At the beginning of the season, the number of yards that each subject could drive the ball was computed, and at the end of the season this was done again. The variable recorded for each subject was the number of additional yards (possibly negative) that the subject could drive the ball by the end of the season.
The levels of the factors in this experiment are
A. number of additional yards the subject could drive the ball by the end of the season.
B. beginning, intermediate, and advanced golfers and titanium driver vs. lessons.
C. the six combinations of golfing ability and titanium driver or lessons.